Electrical closure operated switch changeable between normally open and normally closed condition



L. N. LEA ELECTRICAL CLOSURE OPERATED SWITCH CHANGEABLE 'Nov. 17, 1970 BETWEEN NORMALLY OPEN AND NORMALLY CLOSED CONDITION Filed Oct. '7, 1968 FIGS FIG.8

ATTORNEY.

FIGJO United States Patent US. Cl. 20061.62 8 Claims ABSTRACT OF THE DISCLOSURE One leaf of each of two nested, loose metal hinges are horizontally positioned and assembled with a dielectric piece between them; such assembly having a mounting element. Their other leaves hang downwardly. The downward leaf of the inner hinge, when swung upwards, for instance by the opening of a door or drawer, will cause the other downward leaf to swing upwards, and depending upon the arrangement, the circuit in which said hinges are interposed, will be opened or closed. For a set-up to constitute a normally open switch, said downward leaves are spaced when at normal rest position. To be a normally closed switch, the downward leaf of the outer hinge, at normal rest position, rests on the knukles of the inner hinge, and the face of the downward leaf of the inner hinge, which is opposite the downward leaf of the outer hinge, has an insulative tape covering. Arrangement is also provided to convert from one type to the other, by change of position of the horizontal leaf of the outer hinge. Means are also provided to avoid over movement of the downward leaves.

SPECIFICATION The present invention relates to electrical switches, and more particularly to th type known as trip switches for use in the protective circuits of burglar alarm systems.

The principal object of this invention is to provide a novel and improved trip switch of the class mentioned, which is adaptable for use in either open or closed protective circuits of burglar alarm systems, and such switches can be manufactured for use only in one of said types of circuits, or in a manner so with a slight change to be made by the installer, it is suited for use in any type of circuit he chooses.

Another object thereof is to provide a trip switch of the character described, which automatically returns to initial condition after being actuated and the protected opening closed.

A further object of this invention is to provide a novel trip switch of the character described, which is of simple and improved construction, easy to install, reasonably cheap to manufacture, easy to convert to suit open or closed circuit, if it is of such feature, and which is efiicient in carrying out the functions for which it is designed.

Other objects and advantages will become apparent as this disclosure proceeds.

For one practice of this invention, the switch comprises two loose metal hinges placed in nested relation so one leaf of each is in a horizontal plane as well as their axes, while the other leaves of said hinges hang downward. The distal end of the lower horizontal leaf is bent upward to provide a mounting bracket for the assembly of the horizontal leaves and a dielectric piece between them which is done with screws into said piece. The inner downward leaf is biased by a spring to vertical position. Stop elements extending from the upper hinge components, limit the upward movements of the, outer downward leaf. The position of the upper horizontal leaf will determine whether the switch device formed, is normally in open condition, of in closed condition. Ap-

propriately positioned screw holes in said dielectric piece, afford the dilfe rent positions of mounting the upper horizontal leaf. To be a normally open switch, the downward leaves are in spaced relation at normal rest position. To be a normally closed switch, the downward leaf of the outer hinge, at normal rest position, rests on the kunckles of the inner hinge, and the face of the downward leaf of the inner hinge, which is opposite the downward leaf of the outer hinge, is provided with a insulative tape covering, which may be of the pressure-sensitive type, easy to remove when the desired arrangement to be made is to have a normally open switch. Each hinge is a terminal of this switch device.

In the accompanying drawing forming part of this specification, similar characters of reference indicate corresponding parts in all the views.

FIG. 1 is an exploded perspecitve view of the leaves of the outer hinge.

FIG. 2 is a perspetcive view of the dielctric block on which one leaf of each of the hinges is mounted.

FIG. 3 is a perspective view of the inner hinge, provided with a spring to bias the downward leaf to vertical position.

FIG. 4 shows said spring in perspective.

FIG. 5 is a perspective view of an insulative piece of pressure-sensitive tape, for use when the switch is to be of the normally closed type.

FIG. 6 shows the assembly of the parts illustrated in FIGS. 1-4, to constitute a switch of the normally open type. This switch is shown installed above a door which is closed. This view is a side elevation.

FIG. 7 is a view similar to FIG. 6 showing the switch made to assume closed condition upon opening of the door.

FIG. 8 shows the assembly of the parts illustrated in FIGS. 1-5, to constitute a switch of the normally closed type. This switch is shown installed above a door which is closed. This view is a side elevation.

FIG. 9 is a view similar to FIG. 8, showing the switch of FIG. 8 made to assume open condition upon opening of the door.

FIG. 10 is a fragmentary view of a table, shown partly in section, whose drawer is protected by a switch of FIG. *6.

In the drawing, the switch designated generally by the numeral 15, includes two loose hinges indicated generally by the numerals 1:6, 17, meaning that the leaves 18, 19 are free to turn with respect to each other on their axis pin 20, and that the leaves 21, 22 are free to turn with respect to each other on their axis pin 23. Said hinges are arranged in nested but spaced relation, with said axis pins and the leaves 18 and 21 thereof, horizontally positioned, so it is evident that normally, the leaves 19 and 22 will hang vertically downward, due to the action of gravity. The leaves 18, 21 are assembled with a dielectric spacer 24 between them, by means of screws which extend only part way through said spacer. The spacer is provided with threaded holes therethrough, and said leaves 18 and 21 thereagainst, are provided with clear holes to receive such screws for entry into said threaded holes. The clear holes 25, 26 in the leaf 21 are for the reception of screws which go into the threaded holes 24', 26; only one such screw 27 appearing in the drawing. The clear holes 28, 29 in the leaf 18 are for the reception of the screws 30, 31 which go into the threaded holes 32, 33 in the spacer, which also has another threaded hole 34; the hole 33 being midway between the holes 32 and 34, to facilitate converting the switch 15 which is of the normally open type, to the switch 15' which is of the normally closed type, and vice versa, as will be explained. The unitary structure comprising the leaves 18, 21 and the spacer 24, needs a mounting bracket, which is here furnished by the upright which is made by bending up the distal end part of the leaf 21, which is provided with screw holes 36 and a heightwise slot 37.

When the switch 15 is in its normal rest condition as shown in FIG. 6 where it is mounted on the top rail 38 of the frame of a closed door 39, the leaf 22 extends somewhat below the plane of the top edge of said door, by which it will be intercepted and swung upwardly to make contact with the normally spaced leaf 19, as shown in FIG. 7, thus closing a circuit in which said switch is interposed; said switch being of metal, except part 24, and any screw which is associated with it, serving as a connection terminal of said switch, but chosen so that one is connected to each hinge respectively. It is convenient that the screws 14 and 27 shall be the terminals. Upon closing the door 19, the open switch condition of FIG. 6 is automatically restored.

It is advisable to avoid the leaf 19 swinging up to remain over the leaf 18, should the door he opened rapidly. So, a stop element 40 is provided to limit the upward swing of said leaf 19 so that it shall thereupon be directly for downward movement. Said stop 40 may be struck from the metal of one of the knuckles 41 or 42 of the leaf 18 as shown. It is also advisable to have a rearward stop as shown at 40", to avoid the leaf 19 swinging back to contact the leaf 22 whereupon the switch 15 would be closed, which of course is undesirable in the switch 15. Said stop 40 may be struck from the metal of the knuckle 43. Said stop means may be provided to extend from any part of the hinge 16, which is believed to be readily understood and easily devised without the need of further illustration. Also, in order that the leaf 22 shall discontinue its swing so as to avoid its making contact with the leaf 19 upon the rapid closing of the door, a spring 44 is provided to bias said leaf 22 to vertical position and deaden its momentum. Said spring shown, made of a wire piece, comprises a coil 45 between straight arms in perpendicular relation; said coil being mounted on the axis pin 23, while the arm 46 is held by a strap 47 struck from the leaf 21, and the other arm 48 is held by a strap 49, struck in the leaf 22.

In the arrangement of parts to make the normally open switch 15 as here illustrated, the downward leaf 19, of the outer hinge 16, must not touch the knuckles of the inner hinge 17. This is accomplished by positioning the leaf 18 in the assembly, so its holes 28, 29 register respectively with the threaded holes 33 and 32 in the spacer 24. In the arrangement .of these same parts to make the normally closed switch 15 as herein illustrated, the downward leaf 19 of the outer hinge 16 does normally touch the knuckles of the inner hinge 17, as in FIG. 8. This is accomplished by positioning the leaf 18 in the assembly, so its holes 34 and 33 register respectively with the threaded holes 34 and 33 of the spacer 24. In both in stances, the leaf 22 is of such dimension that its lower edge is below the lower edge of the leaf 19. For the switch 15, the surface of the leaf 22 which faces the leaf 19, is insulated, so upon opening the door 39, the leaf 19 will come on said insulated surface, and the switch 15 will assume an open condition as in FIG. 9. This insulation can be had by use of the insulative tape 51, releasably adhered by having a pressure-sensitive coating 52 thereon.

For the commercial product, it is most practical to make the embodiment 15, so it is ready for use as a normally closed switch which is the type mostly used for the protective circuit in burglar alarm systems. When need be, to convert 15' to 15, leaf 18 is reset to the position shown in FIG. 6, and the leaf 22 is cleaned of the insulative strip 51 and its adhesive coat. Or the product for assembly into either embodiment, can be presented to the market, to comprise the hinge 1-6 as a separate part, so it may be mounted, by use of the screws 30, 31, to its selected position on the balance which is a unit assembly. Then all to be dealt with is the insulative strip 51,

which is left on for the embodiment 15, but removed when 15 is desired.

In FIG. 10, a switch 15 is shown installed so that it shall be closed momentarily upon the opening of a drawer 50 in a table.

This invention is capable of numerous forms and various applications without departing from the essential features herein disclosed. It is therefore intended and desired that the embodiments shown herein shall be deemed merely illustrative and not restrictive and that the patent shall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific showings and description herein, to indicate the. scope of this invention.

I claim:

1. In an electrical switch device of the character described, two conductive hinges, each consisting of a horizontally positioned leaf and a downwardly directed leaf which are hingedly connected in free swinging relation; said hinges being in nested relation, one above the other, means assembling the horizontal leaves insulatively together to form a unitary structure, mounting means extending from said structure; the downward leaf of the lower hinge extending to a plane below the downward leaf of the upper hinge; the downward leaf of the upper hinge extending to a plane which is a predetermined distance below the hinge connection of the leaves of the lower hinge whereby on upward swing of the downward leaf, of the lower hinge towards the other downward leaf, it will contact the lower edge of such other leaf and swing such other leaf upwardly; the downward leaf of the upper hinge being normally in contact with the lower hinge, and dielectric covering on one of said downward leaves so that upon contact of the downward leaves and upward movement of such leaves, the downward leaf of the upper hinge is insulated from the lower hinge.

2. A switch device as defined in claim 1, wherein the leaves of each hinge have knuckles in alignment, and including an axis pin positioned through the knuckles of each hinge respectively; the downward leaf of the upper hinge normally resting on at least one knuckle of the lower hinge whereby said normal contact is established while the downward leaf of the lower hinge is in its normal rest position.

3. A switch device as defined in claim 1, wherein said assembled structure includes a dielectric spacer between the horizontal leaves; said spacer being secured to the lower horizontal leaf and provided with a group of three equally spaced threaded holes along a line perpendicular to the hinge axis of the lower hinge; the upper horizontal leaf having a group of two holes spaced as in the firstmentioned group; said two holes being in register with those two holes in the spacer which are furthest from the hinge axis of the lower hinge, and screws received in registered holes for releasable assembly of said structure so that the upper horizontal leaf can be positioned so the holes therein register with any two holes which are next to one another of said first group; the insulation of any of said downward leaves being removable; the downward leaf of the upper hinge being spaced from the lower hinge when the upper horizontal leaf is set so the holes therein register with those two holes in the spacer which are nearest to the hinge axis of the lower hinge.

4. A switch device as defined in claim 3, including a stop element on the upper hinge to limit the upward swing of the downward leaf of the upper hinge at a predetermined raised position of said downward leaf of the upper hinge.

5. A switch device as defined in claim 3, including a spring on the lower hinge, biasing the lower leaf of the lower hinge to hang vertically.

6. A switch device as defined in claim 5, including a stop element on the upper hinge to limit the upward swing of the downward leaf of the upper hinge at a predeter- 5 mined raised position of said downward leaf of the upper hinge.

7. In an electrical switch device of the character described, two conductive hinges, each consisting of a horizontally positioned leaf and a downwardly directed leaf which are hingedly connected in free swinging relation; said hinges being in nested relation, one above the other, means assembling the horizontal leaves insulatively together to form a unitary structure, mounting means extending from said structure; the downward leaf of the lower hinge extending to a plane below the downward leaf of the upper hinge; the downward leaf of the upper hinge extending to a plane which is a predetermined distance below the hinge connection of the leaves of the lower hinge whereby on upward swing of the downward leaf of the lower hinge towards the other downwards leaf, it will contact the lower edge of such other leaf and swing such other leaf upwardly, and a spring on the lower hinge, biasing the downward leaf of the lower hinge to hang vertically to keep said downward leaf of the lower hinge from swinging upwardly of its own accord and contact the downward leaf of the upper hinge.

8. A switch device as defined in claim 7, including stop elements on the upper hinge to limit the upward swing of the downward leaf of the upper hinge at a predetermined raised position of said downward leaf of the upper hinge, and to stop the downward leaf of the upper hinge to keep it from making contact with the downward leaf of the lower hinge when said downward leaf of the upper hinge swings back towards the downward leaf of the lower hinge.

References Cited UNITED STATES PATENTS 332,661 12/1885 Knoebel 20061.61 X 1,744,333 1/1930 Pfaffenberger 2006l.7 X 2,093,085 9/1937 Ludwig ZOO-6 1.62 3,161,751 12/1964 Pusch et al 200166 3,222,665 12/1965 Tracy ZOO-61.63 X

FOREIGN PATENTS 572,866 2/ 1958 Italy.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDER'HYE, Assistant Examiner US. Cl. X.R. 

